Beta-胡萝卜素与肠道菌群互作效应机制研究

Beta-carotene is an important precursor of vitamin A, while human gut microbiota interacts with β-carotene and affect its absorption, but the mechanism is not yet clear. This project uses anaerobic fermentation in vitro of human intestinal microflora to identify the degradation products of β-carotene metabolized by bacteria, and explore the dose and time effects of β-carotene on the gut microbial structure and biodiversity using bioinformatics analysis, to determine the dominant strains that respond significantly to β-carotene. The characteristics of β-carotene cleavage enzyme were further analyzed by enzymatic analysis, to clarify the interaction relationship between β-carotene and cleavage enzyme as well as the enzymatic hydrolysis site. Then, the metabolic pathway of β-carotene could be revealed and the mechanism of interaction between β-carotene and gut microbiota could be clarified. This project may opens up new approach and provides theoretical guidance for studying the biological potency of carotenoid.

Beta-胡萝卜素是人体重要的维生素A原，人体肠道菌群与β-胡萝卜素互作影响后者的吸收，但其机制尚不明确。本项目用体外人源化肠道菌群厌氧培养技术，鉴定β-胡萝卜素经菌群代谢的降解产物；结合生物信息学分析，探究β-胡萝卜素影响肠道菌群结构与生物多样性的剂量和时间效应，确定对β-胡萝卜素响应显著的优势菌种。进一步通过培养组学和酶学分析法，明确作用菌株β-胡萝卜素裂解酶的特性，解析β-胡萝卜素与肠道菌群代谢酶的相互作用关系与酶解位点，揭示肠道菌群代谢β-胡萝卜素的代谢途径，阐明β-胡萝卜素与肠道菌群的互作机制。本项目为研究类胡萝卜素类营养素的生物效价开拓新的途径和提供基础理论指导。

Beta-胡萝卜素是人体重要的维生素A原，人体肠道菌群与β-胡萝卜素互作影响后者的吸收，但其机制尚不明确。本项目用体外人源化肠道菌群厌氧培养技术，结合生物信息学分析和蛋白组学策略揭示β-胡萝卜素与肠道菌群互作效应及机制。研究结果表明肠道菌群环境发酵24h后，β-胡萝卜素降解率达64.28%，较无菌群处理组提高1.46倍；维生素A表达量较无菌群处理组提高2倍；高中低剂量的β-胡萝卜素均显著影响了肠道菌群结构，β-胡萝卜素显著促进了Roseburia, Parasutterella和Lachnospiraceae菌属增殖，抑制了Dialister, Collinsella和Enterobacter菌属增殖。筛选得到2株β-胡萝卜素降解能力强、重复稳定性好的菌株，经基因组测序鉴定这两株菌分别为Lactobacillus gasseri和Lactobacillus paraplantraum；通过蛋白组学鉴定发现β-胡萝卜素处理后，Lactobacillus gasseri菌株32.6%的蛋白表达差异显著，其中69个蛋白表达上调，83个蛋白表达下调，β-胡萝卜素添加促进了能量代谢通路中蛋白质表达以及丝氨酸、谷氨酰胺、精氨酸相关氨基酸代谢通路的表达。本项目从关键菌株及蛋白表达两个角度阐明了β-胡萝卜素与肠道菌群互作机制，为研究类胡萝卜素类营养素的生物效价开拓新的途径和提供基础理论指导。